On Thursday evening, Elisabeth Murdoch delivered surely the most un-Murdochian speech it is possible for a member of the Murdoch clan to make. Her lecture showed a welcome awareness both of the limits of the market and of the value of publicly funded broadcasters – unsurprising, perhaps, given that the BBC has bought MasterChef and Merlin, among other hits from her production company, Shine. But that should not distract us from the key issues inevitably raised about how diverse Britain's media ever can be while the Murdochs are so dominant.

Delivering the annual MacTaggart memorial lecture at the MediaGuardian Edinburgh International Television Festival, the second daughter of Rupert and sister of James made clear her differences from both men. She took pains to show off liberal sympathies, with references to Havel, Mandela, even Occupy Wall Street. In a subtle hint, she quoted Dennis Potter, the dramatist who so despised News Corp that he named his own cancer "Rupert".

How different from James Murdoch's appearance at the festival in 2009. In his scratchy address, the then-head of News Corp in Europe and Asia laid into the BBCarguing: "The scope of its activities and ambitions is chilling." That speech came to be interpreted as a demand from the Murdochs to the incoming Conservatives: do something about the BBC. It was good therefore to hear Ms Murdoch declare her support, "currently", for the BBC's licence fee funding and opposition to her brother's free-market buccaneering: "Profit must be our servant, not our master." On display here was a different Murdoch ethos. But it is not the one that governs News Corp; as a glance at The Sun's front page on Friday morning, with its nude pictures of Prince Harry, reminds us.

One of the biggest differences between the two Murdochs lies in timing. While her brother spoke before the phone-hacking scandal, Ms Murdoch had to address its fallout. The family business, she admitted, has been forced to ask itself "difficult questions".

To compare the siblings' speeches was like one of those cop-pairings: Good Murdoch, Bad Murdoch. But Murdochs nonetheless. As Ms Murdoch admitted, throughout her career she had been helped and bankrolled by her father. And aided by her surname. She is the third member of her close family to be given this platform, the most prestigious lecture in British broadcasting. What better demonstration of their dominance in British media? One of the conclusions of the phone-hacking scandal is how badly the industry needs greater plurality – whereas up until then it was heading the opposite way. The answer to that conundrum lies not in speeches about values, but in structural reforms. Those will start not in a media gathering, but with Lord Justice Leveson.